This may sound like a joke, but paleontologists believe that the teeth of some tyrannosaurs were shaped so as to purposely accumulate shreds of dead tissue. As these shreds rotted, they bred dangerous bacteria, meaning any non-fatal bite would result in an infected, gangrenous wound. The unlucky herbivore would drop dead in a few days, at which point the same tyrannosaur (or others of its kind) feasted on its carcass.